Centerless grinder



April 6, 948- Hs. INDGE 2,439,303

CENTERLESS GRINDER Filed March 16, 1946 2 sheewsneet 1 HERBERT E5.INDGE;

April 6, 1948. H. s. INDGE 2,4:- 9,3o3`

CENTERLESS GRINDER Filed March 16, 1946 2 Sheets-Sheet 2 Il f 7| 0 l5 lo8 E3 53 `250 4 a h J mmm Y Flg. 5 ,Fi g. 6 3mm HERBERT 5. INDGE @MM .n

'Piana-d Api. s, 194s CENTEBLESS GBINDER Herbert S. Indge, Westborc,Masc., assignmto Norton Company, Worcester,

n tion of Massachusetts Application Maren 1c, 194s, serial No. 654,863

- 8Claims.

'I'he invention relates to centerless grinding machines.

One object of the invention is lto provide a machine ofa characterindicated particularly adapted to grind simultaneously the edges of anumber of thin plates, stones, Jewels, etc.. by temporarily cementingthem together into a single workpiece and applying at each end of suchworkpiece a template or guide of size and shape equal to the final sizeand shape of the workpiece. Another object of the invention is toprovide a centerless grinding machine for grinding a number of pieces ofwork to the same shape and size in one operation. Another object of theinvention is to provide a machine for simultaneously grinding a numberof pieces of 4work in a single operation. Another object of theinvention is to provide a machine of the character indicated in which anumber of pieces of work may be automatically held and rotated against agrinding surface. Another object is to provide a machine for accuratelycontouring a number of objects to the same contour and, in the sameoperation, giving them a good surface finish.

Other objects will be in part obvious or in part pointed outhereinafter. y

The invention accordingly consists in the features of construction,combinations of elements,

and'arrangements of parts, as will be exemplied ln the structure to behereinafter described, and the scope of the application of which will beindicated in the following claims.

In the accompanying drawings in which is shown one of various possibleembodiments of this invention;

Figure 1 is a plan View of a machine constructed in accordance with theinvention;

Figure 2 is a fragmentary rear elevation of the machine showing the endof the grinding wheel spindle and oscillating mechanism therefor:

Figure 3 is a front elevation of the machine;

Figure 4 is a side elevation of the rear of the machine, furtherillustrating the spindle oscillating mechanism; l

Figure 5 is a side view of an assembly of workpieces and templates orguides;

Figure 6 is an end view of the assembly of Figure 5.

Referring to Figures 1 and 3 the machine is mounted upon a base 1.Mounted on the base y1 is an electric motor 8 upon the armature shaft 9of which is a pulley I0 driving, by meansv of belts II, a pulley I2fastened to a grinding wheel Mass., a corpora- 52 I3 are mounted aseries of grinding wheels (three being shown) I1, I8, and I9 which aresurfaced with metal bonded diamonds or other suitable abrasive material.These grinding wheels are bolted ytogether by bolts 20 (one being shown)to form a continuous cylindrical grinding surface. These grinding wheelsare secured together in this manner toform a continuous abrasive surface.because it has been found impossible tov make metal bonded diamondgrinding wheels of the overall axial dimension required.

Compressed against the grinding wheel assembly at either end are a pairof non-grinding master rollers 2I and 22` of diameter equal to that ofthe grinding wheels.y The master rollers 2I and 22 have conical surfaces23 and 24 which fit into similarly shaped recesses in the diamond WheelsI1 and I9 at either end of the grinding wheel assembly in orderaccurately to align the grinding wheels withV the rollers. The masterrollers 2| and 22 are compressed against the grinding Wheel assembly bymeans of a `pair of threaded nuts and 26 on a threaded portion of thespindle I3, and an integral collar 21 on 25 the spindle beyond thepulley I2, thus providing a means for strongly and simply securing themaster rollers 2| and 22 and the grinding wheel assembly I1, I8 and I9to the spindle I3. The spindle I3 and grinding wheel assembly I1, I8 andI9 and master roller 2l and 22 are driven at a speed of the orderv of600 to 1000 revolutions per minute. I

Mounted upon the base 1 and parallel to the axis of the grinding wheelspindle I3 is a'shaft 30 which is journalled in a pair of journalbrackets 3l and32. Mounted upon the shaft 30 is a feed wheel roller 33made of soft rubber which is affixed securely to the shaft 30 to rotatewith it. Mounted securely upon the end of shaft 30 to `drive it is aworm 'wheel 34 which is driven by a worm gear l35 mounted upon the shaft36 of an `electric motor 31 which is mounted upon the base 1 of themachine. The feed roller 33 is driven at a speed of the order 'of 10revolutions per minute.` The feed roller 33 ,is mounted at such adistance from the grinding wheel assembly I1`, I3, and I9 and masterrollers 2I and' 22 that work may be placed on and between the feedroller 33 and the grinding wheel assembly.

'Referring to Figure 3, the feed roller 33 rotates counterclockwise,that is upwardlythrough the 1 grinding throat, and drives .theworkpiececlockspindle I3. The spindle I3 is rotatably mounted Wise. The wheelsI1, I3, and I9 also rotate upwardly in the grinding throat that isclockwise.

Rotatably mounted on a shaft 33 which rotates in slots 39 and 40 inupper bracket extensions 4I and 42 of journal brackets 3| and 32 is aheavy rubber pressure roller 43 of a diameter of the order of less thanhalf that of the grinding wheel assembly I1, I8, and I9 and its masterrollers 2l l and 22. When work is placed on and betweengrindingwhelassembly I1, I8, and I9 and feed roller 33' this pressureroller 43 rides on the work, holds it against the grinding surface I1,I8, I9 and also against the rubber feed Vroller 33.

Referring to Figures, 1, 2, and 4, mounted upon one end of the grindingwheel spindle I3 is a worm 50 which drives a worm wheel 5I. crank pin 52on the Worm wheel 5I reciprocates a link 53 which reciprocates a lever54 connected to the link 53 by means of a pin 55. Lever 54 movesangularly upon a post 56 and is connected to it by a pivot pin 51. Lever54 is also connected by a pin 58 to shoe 59 which ts around spindle I3between two .collars 60 and I I pinned to spindle I3, so that shaft I3rotates in shoe 59 and is reciprocated rectilinearly along its axisslowly by the reciprocation of shoe 59 against collars 6U and 6I. Thegrinding Asurface of the assembly I1,-l IB, and I9 thus movesrectillnearly against thework as welll as rof-v tationally, and thusinsures the preservation of an even surface on the grinding surfacewhich might otherwise be grooved by a number of hard work pieces againstit. The reciprocation or osto rotate it, the grinding wheels may tempofrarily stop its rotation. butthe action of both the wheels and theroller 33 tend to lift the work so that the roller 33 may turn itslightly. `In

some cases the workpiece is nearly finished in the kcourse of a singlerevolution thereof. Y However grinding and polishing continues until theweight of the assembly 10 is taken by the templates 1I bearing againstthe rollers 2I'and 22.

Only one of the limitless numberA of shapes and dimensions of the masterforms, guidesfor templates 1I to which a number of pieces or work may beground in this machine is shown. Jew..

els,stones, small cams, plates and the like may be cheaply, uniformlyand expeditiously pro..v`

duced in mass by this apparatus in a simultaneous automatic operation. IBecause thealcrpara-v tusl ceases' to grind whenthedesireddimensions-are reached, a number of these machines is desired togrind to exactuniform dimensions are temporarily cemented together by asuitable bonding material, to form a single workpiece or assembly. Apair of guides, or templates 1I of exactly equal dimensions and of the.size and shape to which it is desired to grind the cemented ,work piecesor assembly 10 simultaneously, are .cemented to thevends of the workassembly 10 eration. 1

Enough pieces of work are cemented together Figures 5 and 6 show\theworkpieces 10" before grinding while Figures 1 and 3 showthe workpieces1I]4 at the end of the grinding op` can be easilyv tended by oneproduction purposes. y

It will thus be seen vided by this invention a method and an apparatusin which the various objects-hereinabove set forth together'with manythoroughly practicaly advantages are successfully achieved.

As various possible embodiments might be made of the mechanical features.of the above invention and as the art herein described mightbe variedin. various parts, lall Without departing from the scope of theinvention,` it is to be understood that all matter hereinbefore setAforth or shown in the accompanyingdrawings is to be interpreted asillustrative and not in a limiting sense. A I 1 l' I claim:

l. An .apparatus for simultaneously grinding a number of workpieces toa' uniform `shape and dimension with automatic control comprising-afcylindrical. grinding wheel, means torotate said wheel, a feed rollerparallel to the axis of said grinding wheel to rotate said workpiecesagainst- 4- said grinding wheel to 'grind them all'ar'ound,4

for an operation to make a single work assembly 10 to be ground ofnearly equal length to the length of the total grinding surface of thegrindingwheel assembly I1, I8 and I9 as shown. The

work assembly 10 and templates 1I thuscomprise a single unit which isplaced on and between the rubber feed roller 33, and the grinding wheelassembly'l1, I8 and I9, as shown, so

that each of the templates 1I will ride opposite onevof the masterrollers 2l and 22. Pressure roller- 43 is then placed in the slots 39and 40 to ride upon the Work assembly 10 and hold it down. Drivingmotors II and 31 are then ener-4 gized.

the work assembly 1 0 it grinds the pieces ce-r l As the grindingsurface of f grinding wheelassembly I1, I8, and I9 revolves and re-l lciprocates 4rectilinearly alongits axis againstmented together in theassembly .10 uniformly.

The rubber feed roller 33 rotates in adirection opposite to that of thegrindingwheel as.'4 y sembly I1,. I8, and I 9 which is the same as say.

- hlthat bOth the roller 33 and 'the' Wheels II,l

means to drive said feed' roller, a free running roller parallel to theaxes of said grinding wheelV and feed roller to press said workpiecesagainst said feed roller and grinding wheel, a'pair of non-grindingguide rollers at either end of said grinding wheel of diameter equal toit, a pair of templates or form guides of the size and dimensionrequired of said. workpieces which'v maybe cemented to the ends of avwork assembly so that.

when said Work yassembly is placed againstfsaid grinding wheel and feedroller, said templates will ride opposite said non-grinding guide-rollers at' the ends of. `said grinding wheel and ride upon linearlyalong its axis.

` 2. An apparatus for simultaneously grinding-laA number of workpieces--which "-arej t e1n1:|orarily cemented together to form ajcolumn into au niform shape and size witharr automatic control 'to/stop saidgrindingoperation after said. workf pieces are ground 'to said size andsh ape,-'.c`Jmv 'prisinga cylindrical grinding wheel, 'afeedroller' tofeed said column of workpieces to thegrinding surf ace, hold -it,parallel to 'said grinding surface operator for mass' and rotate itagainst said grinding surface, a pair of guide templates which are cutto thesize and shape to which *it is desired to-grind said workpiecesand cemented to the ends of the column of said workpieces, and a pair ofnon-grinding guide rollers of the same diameter as said grinding wheelat each end thereof upon which said guide templates ride to preventfurther grinding when said workpieces are ground to the size of saidguide templates.

3. In an apparatus of the class described, a grinding wheel having anexterior cylindrical grinding surface. means to rotate said grindingwheel about its axis at a relatively high speed, a feed wheel having anexterior cylindrical surface mounted with its axis parallel to the axisof the grinding wheel and close enough to it to form a grinding throatfor grinding workpieces of diameter less than the grinding wheel andless than .the feed wheel, means to rotate said feed 'wheel binationwith the parts and features therein specified, oi' rollers coaxial withthe grinding wheel, one on each end thereof, to form a stop forengagement with templates secured to a. workpiece to limit the grinding.V

Y 5. In apparatus as claimed in claim 3, the com# bination with theparts and features therein specied, of means `to rotate said grindingWheel and said feed wheel so that the direction of motion of thesurfaces of both of said wheels through the grinding throat is towardthe thirdl wheel.

6. In apparatus as claimed in claim 3. the combination with the partsand features therein `specifled of a spindle reciprocator to reciprocatethe grinding wheel along its laxis and against said workpieces as saidgrinding wheel rotates.

` HERBERT S. INDGE.

REFERENCES CITED The following references vare of record in the aboutits axis at a relatively slow speedand in an 20 me of this patent:

angular direction opposite to that of the grinding wheel, a third wheelhaving an exterior cylindrical surface, and a guide for the third wheellocating it on one side of the throat and substantially parallel to theaxes of the grinding `wheel and feed wheel but permitting movement intoand away from the throat.

4. In apparatus as claimed in claim 3, the coml,UNI'I'aD s'rA'r'EsPATENTS l Binns Aug. 20, 1935

